1. Field of the Invention
The present invention relates to an on-spot selectively activated hydrophobic slide/microarray and the preparation method thereof. More particularly, it relates to a hydrophobic copolymer prepared by blending, grafting or co-polymerization of a hydrophobic material and a compound bearing functional groups protected by a protecting group. The hydrophobic copolymer is coated on a substrate and subjected to selective photolithographical activation to form an on-spot selectively activated hydrophobic slide. The slide can then be used to produce an on-spot selectively activated hydrophobic microarray.
2. Description of the Related Arts
In current biochip and bio-microarray technology, most preparation methods involve the treatment of a matrix surface with silanization, followed by crosslinking reaction with biomaterials. In the silanization treatment, the surface of the substrate is activated based on its material, and then treated by a hydrophilic silane such as APTES (amino-propyl-tetraethoxy-silane). Afterwards, the crosslinking reaction is performed via a crosslinker such as glutaraldehyde to immobilize biomaterials on the substrate. The shortcomings of this method include substrate dependence, long reaction time, poor homogeneity, low reaction efficiency, and the resulting low activity for the immobilized biomaterials. Moreover, the prepared covalent bonding surface is hydrophilic, which facilitates crossover and contamination among spots when the hydrophilic surface is used for a high-density microarray.
U.S. Pat. No. 5,837,860 and WO 98/39481 disclose the treatment of glass or silicon wafer with hydrophobic silane such as mercapto-silane, and the immobilization of nucleic acid probes thereon. The method involves treating a substrate surface so that mercapto-groups (HS-) with hydrophobicity are covalently bonded thereon. The hydrophobic property is suitable for the immobilization of nucleic acids/nucleotides in high density. The method, however, requires the modification of the biomaterials to bear mercapto-groups, thereby forming disulfide bonds between the modified biomaterials and matrix surface. Blanchar, A. P. et al. (Biosensors and Bioelectronics, 1996, 11(6/7): 687–690) discloses coating photoresists onto a substrate and then development using the micro-electromechanical mask to form on-spot hydrophilic spots, wherein the region outside of the spots is hydrophobic. The preparation of high-density nucleic acid probe microarrays and in situ synthesis is carried out on this treated surface.
In this prior art, blending, grafting or co-polymerization of a hydrophobic material and a compound bearing functional groups such as imide, cyclic amide, and to prepare a hydrophobic copolymer is not disclosed. Further, the application of the prepared hydrophobic copolymer onto an organic or inorganic substrate to form an on-spot hydrophilic enhanced slide is also not disclosed.